Ch11 Test 2 Spring Semester

Question 1

2 tools to control scatter:

Answer 1

Grids

Beam restricting devices

Question 2

The primary effect in reducing patient doses is:

Answer 2

Proper collimation

Question 3

3 primary factors that contribute to intensity of scatter:

Answer 3

Kvp
Field size
Patient thickness

Question 4

Approximately, _____ % of X-rays are incident on th patient to reach the IR

Answer 4

1%

Question 5

If we increase kvp, we increase scatter which results in _______ contrast.

Answer 5

Decreased

Question 6

Increased field size results in _______ scatter.

Answer 6

Increased

Question 7

Increased patient thickness, _______ scatter

Answer 7

Increases

An extremity will be much sharper of an image

Question 8

The use of a compression device lowers patient dose and also ________ improves.

Answer 8

Spatial and contrast resolution

Question 9

Image forming X-rays consist of both:

Answer 9

Transmitted(pass thru w/out interaction

Photoelectric absorption

Question 10

2 devices remove scatter:

Answer 10

Grids

beam restrictors

Question 11

3 types of beam restrictors:

Answer 11

Aperture diaphragm
Comes/cylinders
Variable aperature collimator

Question 12

A lead or lead lines metal diaphragm attached to the X-ray tube

Answer 12

Aperture diaphragm

Question 13

Modification of the aperature diaphragm. An extended metal restricts beam to circular image

Answer 13

Cones/cylinders
Cylinders are most common
Cones used in Dental

Question 14

Most all machines use this beam restrictor. Has an automatic PBL,
3 mm lead thickness

Answer 14

Variable aperature collimator

Question 15

Mandated by the us food and drug administration in 1974.

Answer 15

Positive beam limitation

PBL

Question 16

14x17 to 10x12 ….^ mAs to _______
“…….” to 8x10…….^ mAs to________
“……” to 5x7……….^ mAs to ________

Answer 16

25-35%
40%
60%

Question 17

The _________ Grid frequency; the _______ your technique

Answer 17

Higher, higher

Question 18

Moving grids can be either of the 2 types of grids

Answer 18

Parallel or

Focused

Question 19

With a parallel grid; the biggest disadvantage is

Answer 19

Grid cutoff

Question 20

Moving Grids can be either of these two:

Answer 20

Reciprocating (back n forth)

Oscillating (circular motion)

Question 21

The higher the grid ration; the ______ Bucky factor!

Answer 21

Higher

Question 22

Bucky factor increases with ______ KVP

Answer 22

Increased

Question 23

We will have ______ grid cutoff with a 5:1 than a 12:1

Answer 23

LESS!!

Question 24

What does the Bucky factor measure??

Answer 24

Primary radiation

Scatter (secondary) radiation

Question 25

Image contrast is approximately ______ when grids are used!

Answer 25

Doubled

Question 26

OD optical density and contrast is

Answer 26

Compton scattering

Transmitted

Question 27

High Kvp results in
Low kvp results in
Which type of X-ray interaction:

Answer 27

*Increases Compton scatter
Photoelectric decreases

*Photoelectric increases!!

Question 28

Interspace material (between the lead; the structure) can be what material:

Answer 28

Aluminum

plastic fiber

Question 29

Aluminum has 2 advantages:

Answer 29

Nonhygroscopic -doesn’t absorb moisture like plastic fiber does

High quality material

Question 30

Fiber grids are preferred bcuz of lower patient dose.

Aluminum has less visible grid lines but:

Answer 30

Increased patient dose!

Question 31

4 types of grids:

Answer 31

Parallel
Crossed
Focused
Moving

Question 32

What does the autotransformer do ?

Answer 32

Kvp selector
Has one winding, one core
Primary and secondary side

Question 33

Where is the mA meter ?

Answer 33

Secondary winding of the high voltage generator side

Question 34

What is a rectifier and where is it?

Answer 34

Converts ac-dc
It’s in the high voltage section
(Secondary side)

Question 35

The release of electrons from getting “boiled off” is called

Answer 35

Thermionic emission

Question 36

The filament is made of what material ?

Target is made of?

Answer 36

Copper

Tungsten

Question 37

3 phase, 6 pulse
3 phase, 12 pulse
high frequency

Answer 37

14%
4%
Less than 1%

Single and full wave are 100%

Question 38

What determines the heat in the filament?

Answer 38

mA

Question 39

Cloud of electrons is ?

What is the X-ray source?

Answer 39

Space charge

Focal spot

Question 40

Where is the focusing cup?

Answer 40

Cathode side

Negative charge

Question 41

When using The heel affect, less radiation is on the anode side. Therefore, place the thicker body on

Answer 41

The cathode side